Derivatives of dihydrocarbyloxyphosphinyl thioformic acids and preparation of the same



tates This invention relates to organic phosphorus compounds containing sulfur. In one aspect, this invention relates to organic phosphorus compounds which contain a sulfur atom linked to the carbon atom of a phosphinyl group. In another aspect, this invention relates to alkali metal dihydrocarbyloxyphosphinyl thioformates wherein an alkali metal atom is directly linked to the sulfur atom of the dihydrocarbyloxyphosphinyl thioformic acid group. In another aspect, this invention relates to S- alkyl-dihydrocarbyloxyphosphinyl thioformates wherein said alkyl radical is directly linked to the sulfur atom of a dihydrecarbyloxyphosphinyl thioformic acid group. In another aspect, this invention relates to methods for preparing alkali metal and alkyl derivatives of dihvdrocarbyloxyphosphinyl thioformic acids.

Numerous organic compounds containing both sulfur and phosphorus atoms are known to exist and to have considerable commercial value in a great variety of useful applications. Although many sulfur-containing phosphorus compounds are derived from the phosphonic acid group, these compounds are usually characterized by the attachment of the sulfur atom directly to the phosphorus atom by a PS bond. Itis desirable to form other sulfurcontaining organic phosphorus compounds having vari ous functional groups, such as the carbonyl group, incorporated therein since such compounds would probably have new uses and applications.

We have discovered that carbonyl sulfide can be used as a reactant to form organic compounds of sulfur and phosphorus having a phosphiuyl phosphorus atom sep- An object of this invention is to provide neworganic phosphorus compounds wherein a sulfur atom is linked directly to the carbon atom of the carbonyl group which is linked directly to a phosphinyl phosphorus atom.

Another object of this invention is to provide alkali metal dihydrocarbyloxyphosphinyl thioformates. as new compounds.

Another object of this invention is to provide S-alkyl dihydrocarbyloxyphosphinyl thioformates as new compounds.

Another object of this invention is to provide methods for producing derivatives of dihydrocarbyloxyphosphinyl thioformic acids.

Other aspects, objects and advantages of the invention are apparent from a consideration of the accompanying disclosure and the appended claims.

According to the present invention, alkali metal salts of hydrocarbylphosphite diesters are reacted with carbonyl sulfide to form alkali metal salts of dihydrocarbyloxyphosphinyl thioformic acids as new compounds, according to the reaction which proceeds substantially as follows: t

(I) 3'0 0 R'O wherein R is a hydrocarbyl radical containing fi'om l to 12 carbon atoms and selected from the group consisting of alkyl, aryl, alkaryl, and aralkyl radicals and M p I 1 Patented Oct. :11, 1 9 61 is alkali metal selected'from the group of V 7 sodium, potassium and lithium. The expression hydrocarbyl as used herein and in, the appended claims refers to the radical obtained by the removal of a hydrogen atom from any hydrocarbon.

Further, according to the present invention. alkali metal salts of dihydrocarbyloxyphosphinyl thioformic acids are reacted with a compound of the formula RY wherein R" is an alkyl radical of from 1 to 8 carbons atoms and Y is an easily replaceable group such as a sulfate, sulfonate, or halide group, according to. the reaction which proceeds substantiallyv as follows: 7

wherein R, R" and M are as above defined and' Yis an,

easily replaceable group selected from the group consisting of -0 -o-z", -o-s -z and -x .wherein R is as above defined and G' is selected from the group consisting of sodium, potassium, lithium and alkyl, said alkyl containing from, 1 to & carbon'atoms.

" The aikai'fmetalphospltitefiieSterreactantsfniployefi' in Reaction 1 can be any sodium, Potassium or lithium salts of -a hydrocarbylphosphite'diester wherein said hydrocarbyl radical is substantially freeof acetylenic unsaturation and which contains from 1 to 12 carbon atoms. 1 Suitable hydrocarbyl radicals include the alkyl, aryl,

alkaryl, and aralkyl radicals. Examples of suitable phosphite diesters include the sodium, potassium and lithium, dimethyl, -di(nebutyl) dietliyl, his(tert-.amyl), bis;(2+ y xyll, d phenyl', ib yL dimly-1,. b p beta-naphthyl), bis(4-biphenyl), bis(para-ethylphenyl), and bis(2-phenylethyl)phosphites.

The alkali metal hydrocarbylphosphite diester reactants may be; produced by variousprocedures known in the art. Preferably, these reactants are. prepared by reacting hy-v drocarbyl hydrogen phosphite dissolved. in a solvent, such as. benzene with sodium hydride suspended in diethyl ether. However, this invention is not limited bythe method bywhich'the alkali metal salt of the; hydrocan bylphosphite .diester is prepared.

Illustrative examples of the alkali metal salts of diliydrocarbyloxyphosphinyl thioformic acid obtained as a product in Reaction I are as follows; sodium; potassium or lithium diethoxyphosphinyl' thioformate; sodium, potassium or lithium dimethoxyphosphinyl thiofonnate; sodium, potassium or lithium dioctoxyphosphinyl thioformate; sodium, potassium or lithium: dibutoxypho-sphinyl thioformate; sodium, potassium or lithium. diphenoxyphosphinyl thioformatmaud sodium, potassi ullor lithim d nzy ox ph sphiuvli thioformate- The compound of the formula R"Y reacted with the 3 alkali metal di-hydrocarbyloxyphosphinyl thioformate in Equation 11 is a compound wherein Y is an easily replaceable group, such as sulfate, sulfonate, or halide group, and R" is an alkyl radical of from 1 to 8 carbon atoms. Thus, Y can be asulfate of the formula j V j: -?OOZ' ,4 g V a sulfonate of the formula or a halide of formula -X. R" in the above formulas can be methyl, ethyl, propyl, n-butyl, n-hexyl, or the like. Z in the above sulfate formula can be the same or difierent from the R", but Z' is preferably the same as R" so that the sulfate is dimethyl sulfate, diethyl sulfate, or the like. Z" in the above sulfonate formula can be either an alkyl or an aryl group, including halo and alkyl substituted derivatives of the alkyl and the aryl sulfonates. Illustrative examples of suitable sulfonate reactants include methyl benzenesulfonate, ethyl benzenesulfonate, methyl chlorobenzenesulfonate, methyl bromobenzenesulfonate, methyl toluenesulfonate, methyl ethylbenzenesulfonate, methyl xylenesulfonate, methyl ethanesulfonate, methyl 2-chloroethanesulfonate, and the like. The halide reactant in the above formula can be either alkyl bromide, alkyl iodide, or alkyl chloride, and preferably the halide is methyl iodide.- Illustrative examples of the S-alkyl dihydrocarbyloxyphosphinyl thioformates formed as a product in Reaction II are: S-methyl diethoxyphosphinyl thioformate, S-ethyl diethoxyphosphinyl thioformate, S-methyl ,dimethoxyphosphinyl thioformate, S-propyl dibutoxyphosphinyl thioformate, S-methyl diphenoxyphosphinyl thioformate, S-methyl dibenzyloxyphosphinyl thioformate and the like.

The reaction of the alkali metal phosphite diester with the carbonyl sulfide set forth in Reaction I is very exothermic and the alkali metal phosphinyl thioformate product produced is relatively unstable at elevated temperature so that this reaction is normally conducted at low temperatures. In general, a temperature within the range of from lO0 C. to +150 C. is used and preferably the temperature is within the range of -80 C. to +25 C. The use of temperatures in the upper portion of the broad temperature range given normally requires the use of elevated pressure to prevent decomposition of the product. However, elevated pressures are not ordinarily required and the reaction can be carried out at subatmospheric and atmospheric as well as superatmospheric pressures. Usually, the reaction is carried out using an inert solvent, such at tetrahydrofuran, benzene, toluene, diethyl ether, dioxane, hexane, diethylcarbitol and the like. The solvent used should be one in which the alkali metal phosphite diester is soluble at the reaction temperature and which has a low freezing point or at least does not freeze at the reaction temperature selected. The selection of the particular solvent also depends upon whether the alkali metal phosphinyl thioformate product is to be separated and recovered as product of the process or is to be further reacted with the compound of the formula RY as shown in Reaction II. If Reaction ]1 is to be carried out, it is preferred that a solvent such as tetrahydrofurfuran in which the alkali metal phosphinyl thioformate product of Reaction I is soluble be used; however, if the alkali metal phosphinyl thioformate product is to be recovered from Reaction I, it is preferred that diethyl ether in which the product of Reaction I is insoluble be employed as the solvent for ease of separation.

Reaction I is preferably carried out by bubbling the gaseous carbonyl sulfide into the solvent solution of alkali metal phosphite diester for a period of time until the exothermic heat of reaction ceases. However, the reaction can also be conducted at a temperature below -50 C., the boiling point of carbonyl sulfide, with liquid carbonyl sulfide and in" this method of conducting the reaction, the alkali metal phosphite diester solution is preferably added slowly to the liquid carbonyl sulfide solution. Thus, the reaction of Equation I can be carried out with either the carbonyl sulfide or the alkali metal phosphite diester in stoichiometric excess; however, preferably stoichiometric amounts are used.

The reaction of the alkali metal phosphinyl thioformate product obtained in Reaction I with the compound of the formula R"Y, as set forth in Equation II, to produce theS-alkyl dihydrocarbyloxyphosphinyl thiofor'mate is usually carried out at temperatures somewhat above the temperatures employed in Reaction 1. Ordinarily, a temperature within the range of from -30 C. to +50 C. is used and preferably a temperature in the range of from 0 to 15 C. Temperatures in the lower portion of the temperature range specified are not particularly desirable since the reaction rate is rather slow and temperatures in the upper portion of the temperature range specified are not normally chosen because various side reactions sometimes occur. It will be noted that.

under some conditions of temperature, Reactions I and II can be carried out at the same temperature. As in Reaction 1, the pressure can be either subatmospheric, atmospheric, or superatmospheric. Also, since the. reaction is somewhat exothermic in nature, it is desirable to conduct the reaction in the presence of an inert solvent. Preferably, the solvent is one in which the alkali metal phosphinyl thioformate produced in Reaction'I is soluble, such as tetrahydrofuran, but any other solvent specified for use in Reaction I can be used. Preferably, stoichiometric amounts of the reactants are employed but an excess of either reactant can be used if desired.

The alkali metal dihydrocarbyloxyphosphinyl thioformate products of this invention are gummy solids which are light in color and insoluble in normal paraffins and diethyl ether and soluble in dioxane, diethyl carbitol. and tetrahydrofuran. These compounds are relatively stable at low temperatures but decompose at temperatures substantially above room temperature. The S-alky-l dihydrocarbyloxyphosphinyl thioformates are relatively stable, colorless liquids. Each of these compounds shows some herbicidal activity. The alkali metal phosphinyl thioformates exhibit activity as soil fumigants whereas the S-alkyl phosphinyl thioformates exhibit actiw'ty as insecticides. These compounds can also be advantageously employed as plasticizers for many plastics and resins, as lubricant and lubricant additives, as corrosion inhibitors, as flame-proofing agents and the like.

The advantages, desirability and usefulness of the new compounds of this invention are illustrated by the following examples:

Example 1 Sodium diethoxyphosphinyl thioformate was prepared in this example by the reaction of sodium diethyl phosphite with carbonyl sulfide. The sodium diethyl phosphite was prepared by slowly adding a solution of 138 g. of diethyl hydrogen phosphite and ml. of benzene to a stirred suspension of 47 g. of sodium hydride (as a 50.9 weight percent dispersion in mineral oil) in 300 ml. of

diethyl ether at a temperature of 5 C. The tempera-' ture of the reaction mixture was maintained at 25 C. with ice cooling. The formation of the sodium diethyl phosphite was completed in approximately 30 minutes; however, the reaction mixture was warmed to 35 C. for an additional 15 minutes.

The diethyl ether solution of sodium diethyl phosphite obtained was then cooled to 5 C. and gaseous carbonyl sulfide was introduced while maintaining the temperature of the mixture between 5 and 25 C. The, int qduction 6 of gaseous carbonyl sulfide was continued during a period dal activity when applied as a spray composition containof one houruntil the rise in temperature due to the exing 0.5% of the chemical to grass and broad-leaf plants,

othermic heat of reaction substantially stopped. The without'exhibiting any activity on bean plants. S-methyl slightly yellow precipitate of sodium diethoxyphosphinyl diethoxyphosphinyl thioformate is also toxic to the mothioformate was separated by evaporation of the solvent bile and resting stages and eggs of two-spotted spider and purified by trituration with hot hexane. The purified mites when applied at a concentration of 0.1% to mitematerial was dried at 0.1 pressure for 22 hours. infested plants. 7 The infrared spectrum of the dried product had a peak at Reasonable variation and modification of the invention 6.3 microns which corresponds to the carbonyl group. as described are possible, the essence of which is that 10 there have been provided alkali metal and alkyl deriva- Example V 1 tives of dihydrocarbylphosphinyl thioformic acids as new 1 111115 p S- y dlathcxypfiosphmyl thlo" compounds and methods for preparing said new comformate was. prepared from the sodium diethoxyphos- Pounds phinyl thioformate obtained in Example 1. This ex- We claim; ample Serves not to PIQVa the structure of 15 1. .An organic phosphorus compound of the formula the sodium diethoxyphosphinyl thioformate obtained in R0 0 0 Example 1 but also to produce the S methyl derivative u n of this new compound.

In this example, the sticky precipitate of sodium diethoxyphosphinyl thioformate obtained after the addiwherein is an hydrocarbyl radical Substantially free non of the carbonyl sulfide was dlssolved by the addmon of acetylenic unsaturation containing from :1 to =12 carof 9 dry teirahydrofuran toform a clear. brown bon atoms and selected from. the group consisting of Sow/Hon Thls 5019mm was added 2 126 of dmethyl alkyl, aryl, alkaryl and aralkyl radicals and Gis selected a Period of 1 hour mm the temperature from the group consisting of alkali metal and alkyl radimaintained in the range of from 5 to 101; C. The rec315 0f from ,1 to 8 carbon atoms action mixture obtained was extracted wit 200 ml. portions of water and the organic phase obtained was dried An orgamc phosphorus compound of the formula with sodium sulfate, filtered and evaporated at 050 fi if C. under 20 mm. pressure to yield a yellow oil in an P-CSM amount of 486.8 g. This yellow oil was fractionally 30 distilled to obtained 101.7 g. fraction boiling in the range a 1 herein R is an hydrocarbyl radical substantially free of 110-120 C. under a pressure of 1.5 t0 3 mm. This w fraction was then redistilled to yield 83.3 g. of S-methyl gg ggfgg lg ggg igg fgg gfi 53 13 3; 2; diethoxyphospchmyl '[hlQfOl'DlfitFQbflllDg ightlhe range 0; alkyl fy alkaryl and aralkyl i an d M an 76.2 to 78.5 at a pressure 0 p mm. 's compoun Z had a refractive index of n 1.4692 and an infrared alkah meta} salected.fr.om the group conslstmg of godlum, potassium and lithium.

spectrum corrmpouding; to the proposed structure. The analysis of the S-methyl diethoxyphosphinyl thioformate Orgamc PhQSPhWS compound of the formula was as follows: 7 KE 40 P-O-B-R" Found Cglplplsagi%fsor R, y 7 wherein R is an hydrocarbyl radical substantially free Percent; oarbonmnn 32.3% 32?? of acetylenic unsaturation containing from 1 to :12 car- Percent Hydmgen bon atoms selected from the On consistin of alk l h 14.92 14.60 gT P g Y 32523? 531%-??? 15. 84 15.11 aryl, alkaryl and aralkyl radicals and R" is an alkyl radical of from 1 to 8 carbon atoms. E l 3 4. Sodium diethoxyphosphinyl thioformate.

In this 2- ts ttmts sarezzzi.sa as;-.. formate was prepared by theadditianaofnalsolutirm lofi z ifi s g c p ydfwafbylrmdg 7' 7 7 i g- 2 m ggg ggg g g gg 3 :51: 2; ical being substantially free of acetylenic unsaturation o lqm car (my 6 m p and containing from 1 to 12 carbon atoms selected from -80 C. in a dry atmosphere, followed by reaction with the group conslstmg of alkyl, aryl, alkaryl, and aralkyl dlmethyl Sulfate" The reacnon mlxmre was Sun-ed and 55 radicals, with carbonyl sulfide md recovering alkali metal the rate of addition of the sodium diethylphosphite solu- 1 d ct f tion was regulated so that a negligible amount of gas esgig gggj thlofonnate as m u o caped from the reaction mixture. After the addition of 7 The I'neflwd which Comprises reacting an alkali g g i g 31 3323 l ggg lg if gz metal dihydrocarbyloxyphosphinyl thioformate said hy sane H mm re drocarbyl radical being substantially free of acetylemc temperature over a one hour period as excess gas esunsaturation and conmmn g from 1 to 12 carbon atoms g 2 3 2 i i igz gi gz g g g g g i fiz selected from the group consisting of alkyl, aryl, al-

lon m u e a P karyl, and aralkyl radicals, with a compound selected precipitate which was removed by filtration. The filtrate from the k group consisting of alkyl sulfates, a1 yl s i -i fi f i l gi gfg gl ffififfg f g ggfi fonates and alkyl halides and recovering from the reac r f r zfciis ihdex of n 26 14683 I tion mixture S-alkyl dihydrocarbyloxyphosphinyl thro- Sodium diethoxyphosphinyl thioformate inhibits the formate as product of f Process. 1k 1 growth of damping ofbfnngiPlrymatotriehamep. lhizws The methcd h @999 R i i a y tom'a solani, Sclerotium rolfsii, Fusarium lycopersz'ci, Vermetal hydmcarbylphosphlte Chester of the formula ticillium alboatrum, and Pythinm sp., when applied to R'O\(") the soil in a concentration of 0.05%. It also exhibits herbicidal activity when applied to grass, beans and broad-leaf plants as a spray composition containing 0.5% i I by weight of the sodium diethoxyphosphinyl thioformate. whereln R is an hydrocarbyl radical substantially free S-methyl diethoxyphosphinyl thioformate exhibits herbiciof acetylenic unsaturation containing from 1 to 12 carbon atoms and selected from the group consisting of alkyl, aryl, alkaryl, and aralkyl radicals and M is an alkali metal selected from the group consisting of sodium, potassium and lithium'with carbonyl sulfide to form an organic phosphorus compound of the formula wherein R and M are as above defined, and then reacting said last formed compound With a compound of the formula R"Y wherein R is an alkyl radical of from 1 to 8 carbon atoms and Y is selected from the group consisting of wherein Z is an alkyl radical of from 1 to 8 carbon atoms, Z" is selected from a group consisting of alkyl, aryl, alkaryl, aralkyl, haloalkyl and haloaryl radicals, and X is a halogen selected from the group consisting of chlorine, bromine and iodine and recovering from the last resulting reaction mixture an organic phosphorus compound of the formula 9. The method which comprises reacting an alkali metal hydrocarbylphosphite diester of the formula wherein -R is an hydrocarbyl radical substantially free of acetylenic unsaturation containing from 1 to 12 carbon atoms and selected from the group consisting of alkyl, aryl, alkaryl and aralkyl radicals and M is an alkali metal selected from the group "consisting of sodium, potassium and lithium with carbonyl sulfide and recovering from the resulting reaction mixture an organic phosphorus compound of the formula \II [I P-CSH RO wherein R and M are as above defined.

10. The method which comprises reacting an organic phosphorus compound of the formula 3'0 0 0 \I! II P-CS-M wherein R is an hydrocarbyl radical substantially free of acetylenic unsaturation containing from 1 to 12 carbon atoms and selected from the group consisting of alkyl, aryl, alkaryl, and aralkyl radicals and M is an alkali metal selected from the group consisting of sodium, potassium and lithium with a compound of the formula R"Y wherein R" is an alkyl radical of from 1 to 8 carbon atoms and Y is selected from the group consisting of a wherein Z is an alkyl radical of from 1 to 8 carbon atoms, Z" is selected from the group consisting of alkyl, aryl,- alkaryl, or aralkyl, haloalkyl and haloaryl radicals, and X is a halogen selected from the group consisting of bromine, chlorine and iodine, and recovering from the resulting reaction mixture an organic phosphorus compound of the formula wherein R and R".are as above defined. V

11. The method of claim 8 wherein said carbonyl sulfide is introduced as a gas into an inert solvent containing said alkali metal hydrocarbylphosphite diester to carry out said reaction.

12. The method of claim 8 wherein said carbonyl sulfide is contacted as a condensed liquid with an inert solvent containing said alkali metal hydrocarbylphosphite diester to carry out said reaction. a 7

13. The method of claim 8 wherein said compound of the formula R"Y and said organic phosphorus compound of the formula are reacted suspended in inert solvents.

14. The method of claim 8 wherein said alkali metal hydrocarbylphosphite diester is prepared by reacting an hydrocarbylhydrogen phosphite suspended in an inert solvent with sodium hydride.

15. The method which comprises reacting sodium diethyl phosphite with carbonyl sulfide to form the sodium diethoxyphosphinyl thiofo'rmate and then reacting said thioformate wtih dimethyl sulfate and recovering S- methyl diethoxyphosphinyl thioformate as product of the References Cited in the file of this patent UNITED STATES PATENTS 2,629,731 Harman Feb. 24, 1953 

1. AN ORGANIC PHOSPHORUS COMPOUND OF THE FORMULA
 8. THE METHOD WHICH COMPRISES REACTING AN ALKYL METAL HYDROCARBYLPHOSPHITE DIESTER OF THE FORMULA 